Adding or creating tabs on your planner depends on the capability of your app. But typically, here's how you do it:
1. You type a text box anywhere on the page, using the lasso tool.
2. Lasso the words then save to photo (on iPad or camera roll).
3. If you have a background eraser app, erase the background of the word.
4. Save the new image (with erased background) once again to your camera roll (or iPad).
5. In app [Goodnotes], bring the image in as a picture.
6. You can adjust the size and rotate the image and place it anywhere on your page.